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CVE-2025-39884

Estado: ModificadaMedia (4.7)—

In the Linux kernel, the following vulnerability has been resolved:

btrfs: fix subvolume deletion lockup caused by inodes xarray race

There is a race condition between inode eviction and inode caching that can cause a live struct btrfs_inode to be missing from the root->inodes xarray. Specifically, there is a window during evict() between the inode being unhashed and deleted from the xarray. If btrfs_iget() is called for the same inode in that window, it will be recreated and inserted into the xarray, but then eviction will delete the new entry, leaving nothing in the xarray:

In turn, this can cause issues for subvolume deletion. Specifically, if an inode is in this lost state, and all other inodes are evicted, then btrfs_del_inode_from_root() will call btrfs_add_dead_root() prematurely. If the lost inode has a delayed_node attached to it, then when btrfs_clean_one_deleted_snapshot() calls btrfs_kill_all_delayed_nodes(), it will loop forever because the delayed_nodes xarray will never become empty (unless memory pressure forces the inode out). We saw this manifest as soft lockups in production.

Leer descripción completaMostrar menos

Fix it by only deleting the xarray entry if it matches the given inode (using __xa_cmpxchg()).

Detalles técnicos trazas, registros y código del informe original
Thread 1                          Thread 2
---------------------------------------------------------------
evict()
  remove_inode_hash()
                                  btrfs_iget_path()
                                    btrfs_iget_locked()
                                    btrfs_read_locked_inode()
                                      btrfs_add_inode_to_root()
  destroy_inode()
    btrfs_destroy_inode()
      btrfs_del_inode_from_root()
        __xa_erase

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

Referencias

JSON original (NVD)

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